bug#49997: 27.2; idle-time reset when switching desktop-page

[martin rudalics]

> Martin, I think everybody agreed that your patch looked like basically
> the right thing, but as far as I can see, it wasn't applied.  Was there
> something more you wanted to check before pushing it, or were you just
> waiting until after the emacs-28 branch was cut (so that it can be
> pushed to master)?

I wanted to understand it first.  Or maybe I was just waiting for Peter
to say that he uses it for quite a while now without problems and if we
could finally install it ...

martin